I would go with a pair of Kribensis. Why aren't you cut out for breeding? I wouldn't suggest more pairs than 1 in a tank that size due to them being very territorial when breeding.
These are mine:
Not as colourful i guess, but you could go with some Fairy Cichlids, they're a very active and intersting small Cichlids. Very beautiful and elegant with their lyretails and bright eyes.
Kribs and a tropical community or even better a species tank of Brichardi, when they spawn the parents will raise the fry then these fry will help raise future generations of fry, really cool tank
These are mine in the same tank as what you have. They're in with a few platties and some gourami's and a few more. I have 4 Lamprologus Brichardi and they stick together and look out for each other very well!
As mentioned you could go with the small shell dwellers Neolamprologus Multifasciatus,
POSSIBLY get away with having 2 pairs in the tank, at either end with clearly defined areas that they can make their own. As for others, i have no experience of, but the Rams are very colourful.
HTH, David.